Converted to Christianity late in life. Married Constantius Chlorus, co-regent of the western Roman empire. Mother of Constantine the Great. Her husband put her aside for a second marriage with better political connections. On his death, her son ascended to the throne, brought her home, and treated her as royalty. She used her high position and wealth in the service of her religious enthusiasm, and helped build churches throughout the empire.

In her late 70’s she led a group to the Holy Land to search for the True Cross. She and her group unearthed three crosses in 326. At the suggestion of SaintMacarius of Jerusalem, she took them to a woman afflicated with an incurable disease, and had her touch each one. One of them immediately cured her, and it was pronounced the True Cross. She built a church on the spot where the cross was found, and sent pieces to Rome and Constantinople; the Feast of the Holy Cross on 14 September celebrates the event. Thus in art, she is usually depicted holding a wooden cross.